Internal threads of internally threaded openings in components can become damaged through wear and other events. As a result of such damage, the load carrying capacity of the damaged internally threaded opening is reduced from the load carrying capacity of the undamaged, original internally threaded opening. The load carrying capacity of internally threaded openings is important as the internal threads may be used to hold, mount, or retain components against operating loads. As used herein, the term “load carrying capacity” refers to the greatest weight that the internally threaded opening can support without reducing its level of performance.
In certain circumstances, the threads of the damaged internally threaded opening can be repaired. Conventional repair methods for repairing components having damaged internally threaded openings include welding. However, welding requires heat that distorts the component and adversely affects material properties. Such distortion may undesirably change component critical dimensions. Therefore, the correction of one problem (a damaged internally threaded opening) may create another problem (changed critical dimensions). Therefore, welding is not a viable option for repairing some components, including critically dimensioned components having damaged internally threaded openings. In addition, it is always a concern when making thread repairs that the original load carrying capacity of the internally threaded opening is restored. The structural integrity of the component is compromised if the original load carrying capacity is not substantially restored. The original load carrying capacity of the damaged internally threaded opening can be restored by using an oversized insert in the damaged internally threaded opening as the bigger the thread size, the more load the internally threaded opening can carry. However, extensive damage or limited wall thickness of the damaged internally threaded opening may prevent even the use of an oversized insert. When the component cannot be repaired with weld repair or by an oversized insert, the component must undesirably be scrapped. Depending on the cost of the component, scrapping of components can be very expensive and can result in manufacturing and operational delays.
Accordingly, it is desirable to provide methods for structural repair of components having damaged internally threaded openings to substantially restore the load carrying capacity thereof and components repaired using such methods. In addition, it is desirable to restore the structural integrity of the component and be able to avoid scrapping components having damaged internally threaded openings, thereby permitting their continued use with consequent savings.